1. Field of the Invention
The present invention relates to a projection display apparatus which includes; a solid light sources; a light valve configured to modulate light emitted from the solid light sources; and a projection unit configured to project light emitted from the light valve on a projection plane.
2. Description of the Related Art
Recently, there has been known a projection display apparatus including a solid light source such as a laser light source, a light valve configured to modulate light emitted from the solid light source, and a projection unit configured to project the light outputted from the light valve on a projection plane.
Here, a long distance between the projection unit and the projection plane needs to be assured for displaying a large-size image on the projection plane. To address this, a projection display system has been proposed which aims to shorten the distance between the projection unit and the projection plane by using a reflection mirror configured to reflect the light, outputted from the projection unit, toward the projection plane for example, Japanese Patent Application Publication No. 2007-334052).
When the projection display apparatus is of a wall projection type, a ceiling plate of the housing case has a transmission area through which light reflected by a reflection mirror passes toward (is projected on) the projection plane. The transmission area may be an opening or may be formed of a transmissive member.
When a laser light source is used as the solid light source, it is desirable that light having been emitted from the solid light source and having passed through the transmission area should be guided only toward the projection plane.